What describes 'thermal stratification' in a hot water tank?

Thermal stratification in a hot water tank refers to the natural phenomenon where water layers are formed at different temperatures. In a typical hot water tank, the hottest water rises to the top while cooler water sinks to the bottom. This layering occurs because warm water is less dense than cold water, causing it to float.

When hot water is drawn from the top of the tank, the cooler water from the bottom is drawn in to replace it, maintaining this stratification. This is particularly important for the efficiency of hot water systems, as it allows for quicker access to hot water without the need for extensive mixing, which can unnecessarily lower the overall temperature of the water in the tank.

Understanding thermal stratification is essential for properly managing hot water systems, ensuring efficient heating, and optimizing the performance of the hot water tank.